Marine superheater.



J. PRIMROSE & G. HARTBR.

MARINE SUPERHBATER.

APPLICATION FILED MAY15, 1911.

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MARINE SUPERHEATER.

APPLICATION FILED MAY 15, 1911.

1,064,250. 1 Patented June 10, 1913.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

JOHN PRIMROSE, OF NEW YORK, AND GODFREY HABTER, OF DANSVILLE, NEW YORK, .ASSIGNOBS TO POWER SPECIALTY COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

MARINE SUPERHEATER.

Application filed Kay 15, 1011. Serial No. 827,100.

To all whom it may concern:

Be it known that we, JOHN Pnnvmosn, a subject of the King of Great Britain, residing at NewYork, in the county and State of New York, and GODFREY HARTER, a subject of the King of Great Britain, residing at Dansv-ille, in the county of Livingston and State of New York, have invented cer-- tain new and useful Improvements in Ma-v rine Superheaters, of which the following is a specification, reference being bad to the drawings accompanying and forming part of the same.

In its broad aspect this invention relates to a device having a heating chamber therein in which heating tubes are located, said heating tubes comprising elements spaced successively closer together in the direction of the flow of the gases to equalize the absorption of the heat throughout the tubes. \Vhile the invention relates broadly to a special means for heating tubes, it is particularly adapted 'for superheaters of the separately fired type, the chief object being in this case to provide a highly efiicient superheater for use on steamships.

Various considerations, as for example. the small space available, the desirability and often necessity of locating heavy pieces of apparatus far down in the hold, etc., make the problem of providing adequate and economical superheatin means for steamships one of peculiar di culty. 8

Our present invention is designed to answer such requirements in an advantageous manner, providing a superheater of most compact orm, so that it will take up the minimum space, and of eflective heat-insulating properties, so that even though of comparatively small size it will have a capacity adequate to the demands made upon it. i

' As further means of utilizing to the utmost the heat, available for superheating purposes the invention includes means for effectively distributing the heated gases among the superheating elements so that.

none of the heating surface of the latter shall be wasted or used inefficiently.

To these and other ends the invention consists in the novel featuresof construction and combinations of elements hereinafter described and more particularly set forth in the appended claims.

The preferred embodiment of the inven-.

tion is illustrated in the accompanying drawings, in which Figure 1 is a longitudinal section. Fig. 2 is a sectional plan view. Fig. 3 is a front elevation, partly in cross section. Figs. 4 and 5 are diagrammatic cross sectional views of modified types of furnace.

The furnace, or each furnace, where more than one is used, is preferably circular in cross section, as indicated in Fig. 3, and consists of an outer shell 10 of heavy sheet metal and an innenwall of fire brick 11. The brick composing the latter are wedge-shaped, that is, have their adyoining faces in radial planes, so that when the inner wall is complete all the bricks composing the same will be rigidly wedged together on the'arch principle. This mode of construction is a markedly advantageous feature of the invention, as it enables fire-brick, a highly refractory material with good heat-insulating properties, to

be used without danger of the'bricks being loosened or disar'ranged by the rolling, pitching and vibration of the ship. The front of each furnace is preferably spherical and composed of an outer front or wall of heavy sheet metal 12, and an inner wall of fire brick 13, the latter composed of crown bricks, that is, tapered on four sides, so as to key themselves in place.

From the foregoing it will be seen that by making the furnace circular or of equivalent form in section so as to be concave toward the fire we are enabled to make it, in effect, of brick, thereby utilizing the advantageous ro rties of that material without risk of injury by the motion or vibration of the vessel.

The grate bars, 14, are supported by a Z-iron'15 at the front, an I-beam 16 at the center, and a channel 17 at the rear of the grate, as shown, the front of the grate be-- ing preferably abo-utrnidway between the top and bottom of the furnace chamber, and the rear slightly lower, so as to give the whole a slope downward toward the back. At the rear of the grate is a bridge wall 18.

As this wall is uite low, it can be made of vided for the removal of ashes from theash pit. In the bridge wall is a hinged door Qt for removal of cinders and the like from the space behind the wall.

The rear end of the furnace may be closed by a checker-wall 22, having numerous apertures for the effective distribution of the furnace gases by dividing the furnace gases into a plurality of currents. This wall may be laid up of fire brick of the ordinary straight form, but to insure the requisite stability'under the motion and vibration of the vessel the bricks are preferably fitted tightly inside the outer wall so as to be bound firmly together thereby.

Back of the furnace is the superheater chamber, preferably rectangular in elevation and plan, composed of inner and outer walls 23, 2;, of heavy sheet metal, with an insulating space between, which, at the sides and top, may be filled with heat-insulating material 244, for example asbestos. The rear wall of the chamber is also in effect double, the inner portion being a heavy sheet metal plate 25 and the outer portion being formed by the wall of the smoke line or stack 26 which extends preferably across the full width of the chamber. Theplate 25 is provided with apertures 27, which may be closed and opened by dampers 28 operable by means of suitable operating rods extend ing along the outside of the furnace to the front, one of said rods being shown at 29. I11 this Way the flow of gases to the stack can be effectively, regulated. Below the stack the chamber is provided with a closured opening 25*, to afford access to the interior of the chamber for cleaning, etc.

In practice we prefer to employ two furnaces, side'by side, with a common superhcating chamber, as indicated in Figs. 2 and 3. The super-heater is located within this common supcrheating chamber,and is preferably composed of transverse inlet headers 30 and transverse outlet. headers 31, con ne'ctcd by supcrheating tubes 32 of inverted U-shape. For the sake of compactness, the headers are staggered, as shown in Fig. 1. The inlet headers are connected to a manifold 32, to which steam is supplied from the boiler or boilers, and the outlet headers are connected to a similar manifold 32, at the other side of the chamber. All the headers rest at their ends on suit-able supports 83, resting on channels 34 fastened to the sides of the chamber. Only one set of supports and channels is shown in the drawing, but itwill be understood that the parts mentioned are duplicated at the opposite side of the chamber. The superheating elements 32 are'prefcrably of the Foster type, composed of steel foundation tubes 35 bent to U-shape and covered with corrugated cast iron for example, in the form of tapered rings 36, the bends being covered with cast iron casings 37. These bends are located in the insulating space between the chamber walls :9 23, 24, so as to minimize liability of injury by heat. At the point where the furnace gases enter the superheating chamber they have their highest temperature, and hence their volume is at the maximum. As they lose heat in flowing past the supcrheating tubes their temperature and volume decrease. Consequently, in order to secure the most efficient utilization of the heat of the gases the cross sectional area of their path should be greatest where they enter the collection of superheating tubes and should diminish as the volume of the gases decreases. In accordance with this principle the first row or rows (two in'the present instance) are spaced relatively far apart, the next two rows are closer together, and the last still closer, as clearly shown in Fig. 2. In this way the flow through the superheater is made more uniform, and at the same time the work is more uniformly distributed among the superheating tubes. Thus, while the first two rowsare subjected to the hottest gases there are fewer tubes in these rows and the total heating surface is smaller. Hence the quantity of heat absorbed by the elements or tubes is smaller, leaving more heat for the nextset of tubes. This set. of tubes, spaced closer together, has a larger total heating surface than the first set, but is subjected to gases of less temperature. and hence absorbs about the same quantity of heat. Similarly the last set, in which the tubes are preferably spaced just far enough apart to allow the gases to pass without undue friction, has still greater heating surface and hence absorbs about the same quantity of heat from the now cooler gases. In this way no set of tubes is overworked, but instead the work is distributed over all with approximate uniformity. As a result the superheater operates more efiicicntly and the tubes have longer life.

It. is desirable, but not absolutely essential to the invention, that the brickwork extend entirely around the fire, underneath the same as well as above. Thus, in Fig. 4, the

arch 40 alone is used, the invert being omitted and its place taken by a sheet metal ash pan 41, the brickwork resting on shoulders 42. The construction shown in Fig. 5

form of the invention, and it is to be under:

stood that the same may be embodied in other forms without departure from its proper spirit and scope as defined by theap- I pended claims.

We claim: I 1. In a marine super-heater, the combina- "tion ofa superheating chamber, a steam superheater therein, and a furnace for supplying hotgases of vcombustion to the chamber, perforated baflie between the furnace and superheating chamber for dividing the furnace gases into a'plurality of currents, a

stack, and regulable means between the chamber and the stack cooperating with the said perforated baffle and causing an equal distribution of the flow of gases through the superheating chamber, I 2. In a steam superheater, the combination of a super-heating chamber, a steam superheater therein, a furnace for supplying hot gases of combustion to the chamber, a brick checker wall between the furnace and the superheating chamber having a plurality of apertures to break up the furnace gases into' a plurality of currents, and a wall between the chamber and the stack having a plurality apertures therein, dampers for said apertures; means to control said dampers independently of one another, whereby an even flow of gases through the superheater may be obtained.

'3. A stack in a-marine superheater, the combination of a superheating chamber, a steam superheater therein, a furnace of cylindrical cross section having its rear end connected to the super-heating chamber to discharge hot gases of combustion thereinto, a wall between the superheater and the stack having a plurality of apertures therein and means to close part or all of said apertures whereby a uniform flow of gases through the superheater may be obtained.

4. In a steam superheater, the combination with a source of heated gases, of a superheater in the path of said gases,com-

prising-superheating elements spaced suc cessively closer'together in the dlrection of flow"of the gases, whereby to equalize the absorption of heat throughout the super,- hea-ter.

5. In asteam superheater, the combination with a source of heated gases, of a steam superheater comprising inlet andoutlet headers transverse to the path of the gases through the superheater, and super-1 6. In a steam superheater, ithe combination of a superh'eatmg chamber having an inlet for'heated gases and an outlet therefor,

transverse .inlet and outlet headers arranged in pairs in the chamber, and U-shaped s erheating tubesconnecting the inlet and outlet headers, the tubes connecting the headers of the pair nearest the chamber inlet being spaced farthest apart and the tubes of the succeeding pairs being spaced successively closer together, whereby to equalize the absorption of heat throughout the superheater. 7. In a marine superheater, the combination of a superheating chamber, a steam superheater therein, a furnace adapted to supply hot gases of combustion to the superheating chamber, a stacksubstantially coextensive with the rear walls of the superheating chamber, a wall between the superheating chamber and the stack having a plurality apertures therein and means to close part or all of said apertures whereby a uniform flow of gases through the superheater may be obtained. I

8. In a marine superheater combination of a substantially horizontal furnace, of a superheating chamber in the rear of said furnace, the walls of said superheating chamber being substantially coextensive with the walls of the furnace, a wall between the furnace and the superheating chamber. having a plurality of apertures therein adapted to cause the hot gases to flow in a plurality of currents a stack in the rear of and substantially coextensive with the walls of the superheating chambers, and- 9. In a device of the class described, the

combination ofa heating chamber, heating tubes located therein, and a furnace for supplying hot gasesof combustion to said chamber, said heating tubes comprising elements spaced successively closer together in the direction of flow of the gases to equalize the absorption of heat throughout the tubes.

In testimonywhereof we aflix our signatures in the presence of two subscribing witnesses. .4

JOHN .PRIMROSE.

GODFREY HARTER. Witnesses to the signature of John Primrose:

D. M. CULLOCH, WM. BOHLEBER.

Witnesses to the signature of Godfrey 

